V 


Circular   No.  40,  Second  Series. 


United  States  Department  of  Agriculture, 

DIVISION  OF  ENTOMOLOGY. 


HOW  TO  DISTINGUISH  THE  DIFFERENT  MOSQUITOES  OF  NORTH 

AMERICA. 

In  Circular  No.  13,  of  this  series,  the  writer  discussed  briefly  the 
habits  of  one  of  our  commonest  mosquitoes  {CuJex  jmngeriH)  and  some 
what  at  length  the  I'emedies  to  be  used  against  all  mosquitoes.     This 
account  was  abbreviated  from  the  more  detailed  treatment  of  the  sub- 
ject in  Bulletin  No.  4,  new  series,  of  this  Division. 

Since  the  publication  of  this  circular  and  of  this  bulletin  wide- 
spread interest  has  been  attracted  to  the  subject  of  mosquitoes  and 
their  habits  and  also  to  the  specific  and  generic  distinctions  which 
exist  between  different  forms.  This  interest  has  arisen  from  the  dis- 
covery that  certain  mosquitoes  are  intermediary  hosts  in  the  develop- 
ment of  the  micro-organisms  of  malaria.  The  connection  between 
mosquitoes  and  malaria,  although  originally  suggested  in  recent  times 
by  an  American  physician,  A.  F.  A.  King,  was  first  demonstrated  by 
experimental  w^ork  carried  on  by  the  English  surgeon,  Ross,  the  Ital- 
ians, Bignami,  Grassi,  and  Bastianelli,  and  the  German,  Koch,  while 
the  American,  McCallum,  has  followed  out  the  life  history  of  a  mala- 
rial parasite  of  the  common  crow. 

The  latest  work  of  the  foreign  investigators  shows  that  not  only  in 
South  Europe  but  also  in  India  and  in  West  Africa  only  mosquitoes 
of  the  genus  Anopheles  are  concerned  in  the  transmission  of  the 
human  malarial  parasite,  although  mosquitoes  of  the  genus  Culex  are 
connected  with  the  transmission  of  the  malarial  diseases  of  birds  and 
possibly  of  other  animals.  These  conclusions  have  been  confirmed  by 
the  Americans,  W.  S.  Thayer,  F.  N.  Berkeley,  and  Albert  Woldert, 
for  America,  so  far  as  their  work  has  gone.  The  latest  announced 
results  of  the  most  advanced  investigators  seem  to  show  that  mosqui- 
toes form  the  principal  if  not  the  sole  means  of  transmission  of  mala- 
ria, and  workers  in  all  parts  of  the  world,  including  many  parts  of  the 
United  States,  are  investigating  the  subject,  more  especially  in  rela- 
tion to  local  conditions. 

In  the  course  of  this  work  there  has  arisen  considerable  difficulty  in 
^(^    the  identification  of  local  species  of  mosquitoes.     The  literature  of 


this  group  of  insects  is  fragmentary  and  scattered.     The  list  published 

in  Bulletin  No.  4,  new 
series,  of  this  office, 
above  referred  to 
(1896),  is  the  most  com- 
plete one  which  has 
been  published  for  this 
country,  and  it  includes 
a  citation  of  very  many 
actual  localities  of  cap- 
ture of  the  different 
species  which  give  us 
the  first  insight  into  the 
geographic  dis  t  r  i  b  u- 
tion  of  the  different 
forms.  Ver}^  many  in- 
vestigators,  mostly 
ph3^sicians,  are  calling 
upon  this  office  for 
assistance  in  the  de- 
termination  of  m o s - 

Fig.  l.—A7iopheles  piinctipeniiis,  female,  with  male  antennae  at  right  qUltOCS,    Or    at     leaSt 
and  wing  tip  showing  venation  at  left— enlarged  (original) .         for   SOUIC  indication  of 

the  characters  by  which  the  different  forms  mav  be  recognized. 

In  answer  to  this  "^^^ 

demand  the  follow- 
ing tables  have  been 
drawn  up  at  the 
writer's  request  bv 
Mr.  D.  W.  Coquii- 
lett.  The}^  include 
all  of  the  mosquitoes 
Avhich  have  been  re- 
corded from  North 
America,  and  com- 
prise, (I)  a  s^^nopsis 
of  the  five  genera 
into  which  the  lonp-- 

o 

beaked,  })lood-suck- 
ing  mos(iuitoes 
known  to  occur  in 
North  America  are 
divided;  (II)  a  syn- 
optic    c()nsid(M'a- 

,.  f     fh  »      .  '        yui.2.—Ciik.v  IrcniorhrincliHS,  fonialo,  showing  the  short  \M\\\n  wliich 

tlOn    Ol      tn(^     species      distinfrnish    Culex   from   Anoplioles;    toothed    front    tarsal   claw  at 
of     the     glMUlS     Alio-      right— enlarged  (original). 

pheles,- divided   into  (a)  the   recognized  forms,  specimens  of   which 


/ 


/ 


3 

occur  in  the  Niitional  Museuin  collection,  jiiid  {h)  the  nnrccoonizcd 
forms,  which  arc  known  only  from  the  literjitiirc;  (III)  a  synoptic  con- 
sideration of  the  species  of  the  o-emis  Culex,  divided  into  ((t)  a  tal)Ic  of 
the  recognized  species,  and  {h)  an  account  of  the  unrecognized  s})ecies; 
(IV)  a  brief  description  of  the  only  valid  known  species  of  the  geruis 
Psorophora;  (V)  a  synoptic  table  of  the  three  known  species  of  the 
genus  Megarhinus;  and  (VI)  a  synoptic  consideration  of  the  two  known 
species  of  the  genus  Aedes. 

So  far  in  the  medical  literature  only  the  genera  Anopheles  and 
Culex  have  received  consideration,  Imt  since  this  circular  is  intended 
simply  to  aid  in  the  identitication  of  the  ditlerent  forms,  the  other 
three  genera  have  been  added  in  order  to  a\  oid  confusion. 


Fig.  3.— Resting  positions  of  Culex  (at  left)  and  Anopheles  (at  right),  enlarged  (redrawn  from  a  rough 
sketch  published  in  the  British  Medical  Journal) . 

The  figures  which  are  given  illustrate  the  structural  points  brought 
out  in  the  synoptic  tables  and  have  been  drawn  by  Miss  Sullivan, 
of  this  office,  under  Mr.  Coquillett's  supervision.  The  figure  repre- 
senting the  difference  in  the  resting  positions  of  Anopheles  and  Culex 
has  been  redrawn  from  a  sketch  made  by  a  member  of  Ross's  expedi- 
tion to  Sierra  Leone.  Neither  the  writer  nor  Mr.  Coquillett  is  able 
to  verify  the  suggestion  that  either  of  these  insects  uniformly  rests  in 
the  positions  indicated,  although  it  is  quite  likely  that  the  attitudes 
shown  are  the  usual  ones. 

RespectfuUv  submitted. 

L.  O. 


Approved: 

James  Wilson, 

Secretary  of  Agriculture. 
Washington,  D.  C,  February  W,  1900. 


Howard, 

Entoriiologid. 


^^\^20^ 


«;T^•Y^ 


plaKT 


SYNOPTIC  TABLES  OF  THE  NORTH  AMERICAN  MOSQUITOES. 

By  D.   W.   COQUILLETT. 

I. — Generic  Synopsis. 

The  following  table  contains  all  the  genera  of  the  long-beaked  mos- 
quitoes known  to  occur  in  North  America.  The  males  are  readih^ 
recognized  b}^  the  antenna  being  densel}^  covered  with  long  hairs;  in 
the  females  the  hairs  of  the  antennae  are  short  and  very  sparse. 

1.  Palpi  in  the  male  at  least  nearly  as  long  as  the  proljoscis,  in  the  female  less  than 

one-half  as  long 2. 

Palpi  in  both  sexes  at  least  almost  as  long  as  the  proboscis Anopheles. 

Palpi  in  both  sexes  less  than  one-half  as  long  as  the  prol)oscis Aecles. 

2.  Proboscis  straight  or  nearly  so,  colors  of  l)ody  ])rown  and  yellowish 3. 

Proboscis  strongly  curving  downward  toward  the  tip,  colors  bluish  or  greenish. 

Megarhinus. 

3.  Legs  bearing  many  nearly  erect  scales Psorophora. 

Legs  destitute  of  such  scales Culex. 

II. — Genus  Anopheles. 

(d)  RECOGNIZED   SPECIES. 

1.  With  a  yellowish  white  spot  near  three-fourths  of  the  length  of  the  front  margin 

of  the  wing;  scales  of  last  vein  white,  those  at  each  end  black. .  pnnctipennis  Say. 
Without  such  a  spot 2. 

2.  Scales  of  last  vein  wholly  black,  palpi  wholly  black quudrimacuhUas  Say. 

Scales  of  last  vein  white,  marked  with  three  black  spots,  palpi  marked  with  white 

at  bases  of  last  four  joints crucians  Wied. 

(h)    UNRECOGNIZED   SPECIES. 

The  following  species  which  have  been  credited  to  our  countrv  have 
not  been  recognized  Avith  certainty;  some  of  them  probably  do  not 
belong  to  the  present  genus,  while  a  few  were  evidently  founded  on 
badly  rubbed  specimens  in  which  the  distinctive  characters  were 
therefore  wanting: 

anxaiVnnanus  v.  d.  Wulp.  I  strongly  suspect  that  this  does  not  belong  to  the  pres- 
ent genus;  the  description  applies  fairly  well  to  the  male  of  Culex  cousobrinus  Desv. 
ferrugiriosus  Wied.  This  author  proposes  this  name  for  the  species  previously 
descril)ed  by  Say  under  the  name  of  Culex  quuKpU'/mckitus,  but  the  description  which 
he  gives  differs  so  decidedly  from  the  one  published  by  Say  as  to  give  the  impres- 
sion that  it  is  founded  on  a  different  species.  I  strongly  suspect  that  the  type  of 
ferrugmosus  is  a  rubbed  example  of  Anopheles  crucians,  which  was  descri])ed  from  the 
same  locality.  Say's  description  of  his  Culex  quinquefasciqtus  agrees  very  well  with 
the  species  which  I  have  identified  as  Culex  impiger  AValker. 

maculipennis  Meigen.  I  strongly  suspect  that  tliis  European  form  is  identical  with 
our  AiKqtheh'x  quadriiuarulafus  Say,  but  this  i)()int  can  not  be  settled  definitely  at 
l)resent,  owing  to  the  lack  of  any  European  specimens  for  comparison  with  ours. 

iilgri]}es  Staeger.  This  Euroiu'an  si)ecies  should  be  readily  recognized  by  its 
uiisj)otted  wings. 

iilh'niKtiiiis  Wied.  Differs  from  our  other  species  by  the  snow-white  apices  of  the 
tarsi. 

Auojiht'les  jiirliiH  Loew  I  think  should  be  placed  as  a  synonym  of  .1.  rruciaux  Wied. 


5 

Our    rcH'oo-nizod    s])oci('s   of    A!i()i)h('l(\s    and    their    synonyms    may 
therefore  l)e  listed  as  follows,  the  synonyms  indented: 

crucians  Wied, 

p ictus  Loew. 

?  ferrugitiosKs  Wied. 
punrtipemii.s  Say. 

hiemalis  Fitch. 
giiadrimaculatus  Say. 

?  macidipennis  Meigeii. 

HI. — Genus  Culp:x. 

{a)  RECOGNIZED   SPECIES. 

Males. 

1.  Front  tarsal  claws  l)earing  a  distinct  tooth  near  the  middle  of  the  nnderside  of 

each 3. 

Front  tarsal  claws  bearing  two  teeth  on  the  underside  of  one  claw,  and  one  on 
underside  of  the  other,  proboscis  destitute  of  a  whitish  band  near  the 
middle , 2. 

Front  tarsal  claws  with  one  tooth  on  underside  of  one  of  the  claws,  none  on  the 
other,  bases  of  tarsal  joints  white,  prol^oscis  destitute  of  a  whitish  band  near 
the  middle fasciatus  Fabr. 

2.  Tarsi  distinctly  white  at  leases  of  the  joints ejcitans  AValk. 

Tarsi  not  white  at  bases  of  the  joints cousohriuus  Desv. 

3.  Proboscis  destitute  of  a  whitish  ring  near  the  middle 4, 

Proboscis  with  such  a  ring,  ends  of  tarsal  joints  white tarmlis  Coq. 

4.  Bases  of  tarsal  joints  not  white 5. 

Bases  of  tarsal  joints  white stimvhois  Walk. 

5.  Petiole  of  submarginal  cell  less  than  one-third  of  the  length  of  that  cell. 

pungevs  Wied. 
Petiole  of  sul)marginal  cell  at  least  one-half  of  the  length  of  that  cell. 

Impigcr  Walk. 
Fetnales. 

1.  Front  tarsal  claws  bearing  a  distinct  tooth  near  middle  of  underside  of  each. . .  2. 
Front  tarsal  claws  destitute  of  teeth 7. 

2.  Proboscis  destitute  of  a  white  ring  near  the  middle 3. 

Proboscis  marked  with  such  a  ring,  bases  of  tarsal  joints  white. 

tcTit iorhipx-Jt IIS  Wied. 

3.  Bases  of  tarsal  joints  distinctly  white 4. 

Bases  of  tarsal  joints  never  white 5. 

4.  ^Nlesonotum  marked  with  four  stripes  of  silvery  scales fasciatus  Fabr. 

Mesonotum  destitute  of  such  stripes stimulans  Walk. 

5.  Last  two  joints  of  hind  tarsi  never  white 6. 

Last  two  joints  of  hind  tarsi  snow  white ])osticatus  Wied. 

6.  Abdomen  marked  with  a  cross  band  of  whitish  scales  at  base  of  each  segment. 

impiger  Walk. 
Abdomen  never  marked  in  this  manner,  but  with  a  cluster  of  whitish  scales  at 
front  angles  of  some  of  the  segments triseriata  Say. 

7.  Proboscis  marked  with  a  distinct  whitish  ring  near  the  middle,  tarsi  white  at 

sutures  of  the  joints 8. 

Proboscis  destitute  of  a  whitish  ring  near  the  middle 9. 


8.  Tarsal  joints  white  at  bases  only perturbans  Walk. 

Tarsal  joints  white  at  both  ends tarsalU  Coq. 

9.  Tarsi  white  at  bases  of  joints 10. 

Tarsi  never  white  at  bases  of  the  joints 12. 

10.  ^Mesonotum  never  marked  with  stripes  of  silvery  scales 11. 

Mesonotum  marked  with  four  stripes  of  silvery  scales,  first  tarsal  joint  never 

marked  with  a  whitish  ring  near  the  middle signifcr  Coq. 

11.  First  tarsal  joint  marked  with  a  whitish  ring  near  middle  of  each .  excrncians  Walk. 
First  tarsal  joint  destitute  of  such  a  ring excitnns  Walk. 

12.  Petiole  of  submarginal  cell  less  than  one-third  of  the  length  of  that  cell. 

pungent  Wied. 
Petiole  of  submarginal  cell  at  least  almost  one-half  of  the  length  of  that  cell. 

consobrinus  Desv. 

(h)    UNRECOGNIZED   SPECIES. 

ammlatus  Schrank,  This  European  species  was  credited  to  our  fauna  by  Osten 
Sacken.  The  description  agrees  fairly  well  with  specimens  which  I  have  identified 
as  e.vcitaris,  Walker,  except  that  in  the  latter  there  is  no  white  ring  on  the  femora 
toward  their  apices. 

boscii  Desv.     Probably  a  rubbed  specimen  of  pungens. 

nigripes  Zett.  Black,  the  legs  of  the  male  dark  yellow,  hairs  of  pleura  of  female 
gray,  a  band  of  white  scales  at  base  of  each  segment  of  her  abdomen. 

rubidus  Desv.  The  description  was  apparently  founded  on  a  rubbed  specimen  of 
Psowphora  ciliata. 

testaceiis  v.  d.  Wulp.     Is  probably  a  somewhat  injured  example  of  consobrinus. 

incidens  Thomson.     Is  evidently  a  synonym  of  impiger  Walker. 

bigoti  Bellardi.  According  to  the  figure  and  description,  the  bands  of  black  scales 
are  at  the  bases  of  the  abdominal  segments;  in  the  recognized  species  these  bands  are 
always  at  the  apices  of  the  segments.  In  other  respects  this  species  must  greatly 
resemble  pungens. 

cubensis  Bigot.     Apparently  founded  on  a  badly  rubbed  specimen  of  pungens. 

frater  Desv.  This  name  was  proposed  for  the  Culex  fasciatus  of  Wiedemann  under 
the  impression  that  this  is  not  the  same  species  as  the  one  described  by  Fabricius 
under  the  same  name.  It  seems  quite  certain,  however,  that  the  word  "  proboscis  " 
in  Fabricius'  description  was  simply  a  lapsus  for  "palpi,"  and  with  this  emendation 
the  two  descriptions  agree  very  well. 

mexicana  Bellardi.     Is  evidently  a  synonym  of  posticatus. 

provocans  Walker.  Is  probably  a  synonym  of  slimulans:  In  some  specimens  of 
this  species  the  light  color  at  the  bases  of  the  tarsal  joints  is  very  indistinct. 

territans  Walker.     Is  apparently  a  synonym  of  pungens. 

Our  recog-nized  species  of  Culex  and  their  synonyms  may  be  listed 
as  follows,  the  synon3^ms  indented: 

consobrinus  Desv. 

?  annuUmanus  v.  d.  Wulj)  (Anopheles) . 

impatiens  Walker. 

inornatus  Williston. 

pinguis  Walker. 

punctor  Kirl)y. 

?  testaceus  v.  d.  Wulp. 
excitans  Walker. 

?  (I niiiUdliis  OAtm  Sacken  (ncc  Meigen,  etc.). 


excruciaiiK  Wal kcr. 
fasdatus  Fal)r. 

frater  DeHv. 

mosquito  Dghv. 

taeniafu!^  Wied. 
imjngcr  Walker. 

implaca h ills  Wal  ker. 

incident  Thomson. 

?  (juinquefasciafus  Say. 
perturbanH  Walker. 
posticatus  Wied. 

?  mexiccmus  Bellardi. 
musicus  Say. 
pungens  ^y  led. 

?  6osm  Desv. 

?  cubensis  Bigot. 

?  territans  Walker. 
signifer  Coquillett. 
stimulans  Walker. 

?  provocans  Walker. 
taeniorhynchus  Wied. 

damnosus  Say. 

sollicitans  Walker. 
tarsalis  Coquillett. 
iriseriatus  Say. 

IV. — Genus  Psorophora. 

Our  single  species  is  of  a  yellowish  color,  usually  varied  with 
brown,  the  bases  of  the  tarsal  joints  white.  It  is  considerably  larger 
than  any  of  our  other  species  of  yellowish  or  brown  mosquitoes: 

ciliatus  Fabr. 

conterrens  Walker. 
molestus  Wied. 
?  rubidus  Desv. 

V. — Genus  Megarhinus. 

Our  three  species  are  among  the  largest  in  this  family,  and  are  not 
known  to  occur  north  of  the  District  of  Columbia.  The}^  may  be 
separated  as  follows: 

All  tarsi  marked  with  white rutila  Coq. 

Hind  tarsi  alone  marked  with  white portoricensis  Koeder. 

None  of  the  tarsi  marked  with  white Juanorrhoidalis  Fabr. 

VI. — Genus  Aedes. 

Our  two  species  are  among  the  smallest  of  our  mosquitoes,  and 
have  a  pale  brownish  ground  color.  The}^  ma}^  be  distinguished  as 
follows: 

Thorax  marked  with  a  median  violet  blue  stripe sapphinniis  O.  S. 

Thorax  destitute  of  such  a  stripe fuscus  O.  S. 


o 


A 


UNIVERSITY  OF  FLORIDA 

Wllllllillllllllllillllllllll 

3  1262  09228  3315 


